Pigeon's recognition of cartoons: effects of fragmentation, scrambling, and deletion of elements

J. Cerella [Pattern Recognit. 12 (1980) 1] and more recently S. Watanabe [Behav. Proc. 53 (2001) 3] demonstrated that pigeons showed no decrement in recognizing cartoons that were spatially scrambled, indicating that pigeons' discriminative responding is controlled by local features alone. In contrast Kirkpatrick-Steger et al. [J. Exp. Psychol. Anim. Behav. Proc. 24 (1998) 34] used line drawings as stimuli and demonstrated the importance of spatial organization for picture recognition by pigeons, confirming related findings reported in their previous studies. The present study revisited the recognition of cartoons by pigeons. In Experiment 1, pigeons were trained to discriminate cartoon people on a variety of background scenes. Subsequent tests revealed that discriminative performances with both familiar and novel instances decreased as the objects and object-like parts were progressively fragmented, indicating that search for the targeted cartoon people in the stimulus array might have enhanced the pigeons to attend to global aspects of cartoon people. Experiment 2 used line drawings of cartoon faces as stimuli and examined effects of scrambling and deletion of components. A set of components (eyes and eyebrows) exerted strong control over behavior and scrambling only moderately suppressed responding. The results suggest that pigeons use both global and local aspects, with different mixtures of these types of information depending on the particular perceptual context.     

In vitro susceptibility to tetracycline and fluoroquinolones of Japanese isolates of Coxiella burnetii

Coxiella burnetii is the agent of the worldwide zoonosis, Q fever. The in vitro susceptibility to tetracycline and fluoroquinolones of Japanese isolates of C. burnetii was evaluated for the first time. The MICs against Japanese isolates were almost the same as the MICs against the foreign reference isolates. The results suggest that the common antibiotics therapy for Q fever used in other countries is also effective for Japanese Q fever patients.     

Tie2/angiopoietin-1 signaling regulates hematopoietic stem cell quiescence in the bone marrow niche

The quiescent state is thought to be an indispensable property for the maintenance of hematopoietic stem cells (HSCs). Interaction of HSCs with their particular microenvironments, known as the stem cell niches, is critical for adult hematopoiesis in the bone marrow (BM). Here, we demonstrate that HSCs expressing the receptor tyrosine kinase Tie2 are quiescent and antiapoptotic, and comprise a side-population (SP) of HSCs, which adhere to osteoblasts (OBs) in the BM niche. The interaction of Tie2 with its ligand Angiopoietin-1 (Ang-1) induced cobblestone formation of HSCs in vitro and maintained in vivo long-term repopulating activity of HSCs. Furthermore, Ang-1 enhanced the ability of HSCs to become quiescent and induced adhesion to bone, resulting in protection of the HSC compartment from myelosuppressive stress. These data suggest that the Tie2/Ang-1 signaling pathway plays a critical role in the maintenance of HSCs in a quiescent state in the BM niche.     

Development and evaluation of an online CO(2) evolution test and a multicomponent biodegradation test system

Well-established biodegradation tests use biogenously evolved carbon dioxide (CO(2)) as an analytical parameter to determine the ultimate biodegradability of substances. A newly developed analytical technique based on the continuous online measurement of conductivity showed its suitability over other techniques. It could be demonstrated that the method met all criteria of established biodegradation tests, gave continuous biodegradation curves, and was more reliable than other tests. In parallel experiments, only small variations in the biodegradation pattern occurred. When comparing the new online CO(2) method with existing CO(2) evolution tests, growth rates and lag periods were similar and only the final degree of biodegradation of aniline was slightly lower. A further test development was the unification and parallel measurement of all three important summary parameters for biodegradation--i.e., CO(2) evolution, determination of the biochemical oxygen demand (BOD), and removal of dissolved organic carbon (DOC)--in a multicomponent biodegradation test system (MCBTS). The practicability of this test method was demonstrated with aniline. This test system had advantages for poorly water-soluble and highly volatile compounds and allowed the determination of the carbon fraction integrated into biomass (heterotrophic yield). The integrated online measurements of CO(2) and BOD systems produced continuous degradation curves, which better met the stringent criteria of ready biodegradability (60% biodegradation in a 10-day window). Furthermore the data could be used to calculate maximal growth rates for the modeling of biodegradation processes.     

Participation of prostaglandin E receptor EP4 subtype in duodenal bicarbonate secretion in rats

We examined, by using a specific PGE receptor subtype EP4 agonist and antagonist, the involvement of EP4 receptors in duodenal HCO(3)(-) secretion induced by PGE(2) and mucosal acidification in rats. Mucosal acidification was achieved by exposing a duodenal loop to 10 mM HCl for 10 min, and various EP agonists were given intravenously 10 min before the acidification. Secretion of HCO(3)(-) was dose-dependently stimulated by AE1-329 (EP4 agonist), the maximal response being equivalent to that induced by sulprostone (EP1/EP3 agonist) or PGE(2). The stimulatory action of AE1-329 and PGE(2) but not sulprostone was attenuated by AE3-208, a specific EP4 antagonist. This antagonist also significantly mitigated the acid-induced HCO(3)(-) secretion. Coadministration of sulprostone and AE1-329 caused a greater secretory response than either agent alone. IBMX potentiated the stimulatory action of both sulprostone and AE1-329, whereas verapamil mitigated the effect of sulprostone but not AE1-329. Chemical ablation of capsaicin-sensitive afferent neurons did not affect the response to any of the EP agonists used. We conclude that EP4 receptors are involved in the duodenal HCO(3)(-) response induced by PGE(2) or acidification in addition to EP3 receptors. The process by which HCO(3)(-) is secreted through these receptors differs regarding second-messenger coupling. Stimulation through EP4 receptors is mediated by cAMP, whereas that through EP3 receptors is regulated by both cAMP and Ca(2+); yet there is cooperation between the actions mediated by these two receptors. The neuronal reflex pathway is not involved in stimulatory actions of these prostanoids.     

Galactonate determination in urine by stable isotope dilution gas chromatography-mass spectrometry

A stable isotope dilution assay was developed for the sensitive determination of D-galactonic acid. D-[U-13C(6)]galactono-1,4-lactone was prepared as internal standard. Unlabelled and U-13C-labelled D-galactonic acid species were converted to the N-(1-butyl)galactonamide pentaacetate derivatives and assessed by gas chromatography-mass spectrometry (GC-MS). Positive chemical ionisation and monitoring of the [MH-60](+)-ions in the galactonate chromatographic peak at m/z 402 and m/z 408 were used for quantification. The procedure was applied to study the variability of D-galactonate excretion in healthy subjects and galactosemic patients and to monitor the D-galactonate-D-galactitol ratio in human urine.     

Determination of trivalent methylated arsenicals in rat urine by liquid chromatography-inductively coupled plasma mass spectrometry after solvent extraction

A method for the determination of trivalent arsenicals in urine was examined. Trivalent arsenicals, extracted as complexes with diethylammonium diethyldithiocarbamate (DDDC) into carbon tetrachloride, were determined by liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS). The trivalent methylated arsenicals monomethylarsonous acid (MMA(III)), dimethylarsinous acid (DMA(III)), and trimethylarsine (TMA) were detected in urine of rats that had received dimethylarsinic acid (DMA(V)) or monomethylarsonic acid (MMA(V)) at concentration of 200 microg ml(-1) in drinking water for 24 weeks. This method is the first to permit quantification of trivalent methylated arsenicals in urine without significant changes in concentration during storage or pretreatment.     

X-inactivation is stably maintained in mouse embryos deficient for histone methyl transferase G9a

One of the two X chromosomes becomes inactivated during early development of female mammals. Recent studies demonstrate that the inactive X chromosome is rich in histone H3 methylated at Lys-9 and Lys-27, suggesting an important role for these modifications in X-inactivation. It has been shown that in the mouse Eed is required for maintenance of X-inactivation in the extraembryonic lineages. Interestingly, Eed associates with Ezh2 to form a complex possessing histone methyltransferase activity predominantly for H3 Lys-27. We previously showed that G9a is one of the histone methyltransferases specific for H3 Lys-9 and is essential for embryonic development. Here we examined X-inactivation in mouse embryos deficient for G9a. Expression of Xist, which is crucial for the initiation of X-inactivation, was properly regulated and the inactivated X chromosome was stably maintained even in the absence of G9a. These results demonstrate that G9a is not essential for X-inactivation.     

Activation of a signaling cascade by cytoskeleton stretch

Cells sense and respond to mechanical force. However, the mechanisms of transduction of extracellular matrix (ECM) forces to biochemical signals are not known. After removing the cell membrane and soluble proteins by Triton X-100 extraction, we found that the remaining complex (Triton cytoskeletons) activated Rap1 upon stretch. Rap1 guanine nucleotide exchange factor, C3G, was required for this activation; C3G as well as the adaptor protein, CrkII, in cell extract bound to Triton cytoskeletons in a stretch-dependent manner. CrkII binding, which was Cas dependent, correlated with stretch-dependent tyrosine phosphorylation of proteins in Triton cytoskeletons including Cas at the contacts with ECM. These in vitro findings were compatible with in vivo observations of stretch-enhanced phosphotyrosine signals, accumulation of CrkII at cell-ECM contacts, and CrkII-Cas colocalization. We suggest that mechanical force on Triton cytoskeletons activates local tyrosine phosphorylation, which provides docking sites for cytosolic proteins, and initiates signaling to activate Rap1.